Kenneth MacMillan's Gloria is a profoundly moving response to World War I. The opening image instantly evokes familiar images of soldiers at Passchendaele or the Somme – men, silhouetted, the distinctive profile of their Brodie helmets clearly visible. But the choreography itself speaks powerfully of the consequences of war and the anguish of loss.

MacMillan's wife Deborah has spoken of how throughout MacMillan's career he had sought to create a ballet in response to war. It wasn't until quite late in his life, in 1979, that MacMillan encountered the spur that would lead to Gloria. A BBC TV dramatization of Vera Brittain's Testament of Youth inspired MacMillan with its elegiac tribute to the lost generation, told through Brittain's own experiences of working as a nurse and of losing both her brother and her fiancé to the conflict. Brittain's story is clearly represented in MacMillan's choreography, through limpid pas de deux and an excoriating, intense pas de trois, where the central woman holds the two men close to her.

But there's also a more directly personal element to Gloria. MacMillan's father William fought in World War I and died of pneumonia in 1946 when Kenneth was 16. William had not supported Kenneth's desire to dance – Kenneth had had to forge a letter from his father in order to audition for Ninette de Valois – and never saw him perform. William's death came at the same time as Kenneth received his first professional contract, and led to a personal crisis for Kenneth. He later wrote that on his father's death 'I was overcome by loneliness… I was unable to give my father the warmth he craved. It was an emotional paralysis that masked my real feelings for years to come.'

William never spoke to his family of his wartime experiences. He had enlisted in May 1915, at the age of 24, as a gunner with the Highland Fifth Royal Garrison Artillery. He was caught in a mustard gas-attack at the Battle of the Somme, which left him with lifelong pulmonary problems and sores on his face and neck. William nursed an intense contempt for the Army authorities, refusing further treatment or a disability pension after his discharge in 1919. He often spoke of moving his family to the Soviet Union. Kenneth later remembered his father forbidding him or his brother from joining the Scouts – his only explanation that he didn't want his sons wearing uniforms.

Many have suggested that Brittain's study of the Great War and its after-effects enabled MacMillan to begin to understand the horrors that his father had experienced, and to begin to unfold the guilt he had associated with his relationship with his father. There's anger in Gloria – the moment in the pas de trois where the three soloists point at the audience, a gesture that recalls the Lord Kitchener enlistment posters while also carrying a clear edge of accusation. There's pessimism too, in the moment where the corps de ballet gather in circular movements, a representation of the unending cycle of peace and war. But MacMillan's choreography also expresses tenderness, yearning and love in movements of intimate beauty. The sadness and horror expressed in Gloria is matched by a profound sense of humanity.

Gloria is a poignant tribute both to the fallen and to those left behind. MacMillan was able to invest his unique choreographic language with a deeply felt emotion. The result is one of his masterpieces, and a true act of remembrance.

Today marks 100 years since the birth of Benjamin Britten, one of the great composers of the 20th century.

Britten’s compositions span classical music forms, from large-scale symphonic scores to songs and choral works. He first achieved international fame in 1945 with the acclaimed premiere of his opera Peter Grimes. One hundred years after his birth, more operas by Britten are performed worldwide than by any other composer born in the 20th century, and he is widely credited with founding a new English-language opera tradition. He also introduced generations of children to music through such works as Noye’s Fluddeand The Young Person’s Guide to the Orchestra, which is now the focus of an iPad app. 'His music really gets under your skin, which makes him stand out,' says Royal Opera Music Director Antonio Pappano.

Peter Grimes is a rare masterpiece of English opera, suffused with an almost overwhelming sense of place; the salty sea air and dark stormy light of Suffolk on the east coast. Its inspiration is Britten’s home town, the unique coastal settlement of Aldeburgh. If you have seen the opera, and never been to the landscape that inspired it, here is a Peter Grimes Trail to inspire you to head East one stormy summer afternoon.

Peter Grimes Trail

1. Aldeburgh Parish Church: The medieval church of Saint Peter and Paul looks out to sea, with an unusually tall 14th-century bell tower once used as a key navigation point by sailors. Britten’s body is buried in the church's Lawn Cemetery. A simple slate headstone marks his grave, which stands next to that of his partner the tenor Peter Pears, who first sang the title role of Peter Grimes.

Inside, near the organ, is a bust of George Crabbe, whose poem 'The Borough' inspired Britten to write Peter Grimes. The church was also the venue for the first concert of the first Aldeburgh Festival in 1948, and for many notable performances since. Near the bust is a stained glass window by the artist John Piper in memory of his friend Britten.

2. The Moot Hall The prologue of Peter Grimes is set in ‘a room inside the Moot Hall, arranged for a coroner’s inquest’. The Moot Hall is Aldeburgh’s oldest building after the church and has been the centre of civic life in the town for more than 450 years. Aldeburgh Town Council still meets in its first-floor chamber, which also houses Aldeburgh Museum. Facing the Moot Hall is the Mill Inn, which also dates from the 16th century and is today one of several fine Aldeburgh public houses that are altogether more salubrious than The Boar (the fictional inn in Peter Grimes where the townsfolk meet to gossip and carouse).

3. Scallop by Maggi Hambling: The interludes in Peter Grimes famously evoke the Aldeburgh shore in all its moods. Its shingle beach was a source of inspiration to Britten throughout his career. On the shingle north of the town, towards Thorpeness, is the giant metal sculpture of a shell, Scallop, a tribute to Britten by the Suffolk artist Maggi Hambling. The four-metre high stainless steel structure is composed of two fractured and interlocking scallop shells, pierced with words sung by Grimes towards the end of the opera: ‘I hear those voices that will not be drowned’. It is a wonderful place to sit and listen to the sound of wind and sea and waves.

4. Stop to eat: The walk between the Scallop and the Moot Hall takes you past the huts of the few fisherman still working out of Aldeburgh. You can buy freshly-landed fish from them, or ready-cooked at either of the two fish and chip shops along the High Street.

5. The Red House: Here, off leafy and secluded Golf Lane, is the house where Britten and Pears lived and worked from 1957 until their deaths. Today it is the home of the Britten—Pears Foundation, which welcomes visitors to to gain new insights into Britten's music in the place where much of it was written. Visitors can browse an exhibition on Britten at work, book onto guided tours of the house, and enjoy the extensive gardens. Be quick – you only have until the end of August to visit; the house is shortly to close for a major building project (due to reopen in 2013).

6. Where to stay: The Old Mill, Snape:Peter Grimes was composed while Britten was living at a converted mill in the village of Snape, just up the hill from the Maltings that he would later turn into a world-class concert hall. The Old Mill is not open to the public, but you can in stay two separate cottages on the site.